Usually, apparatuses for conveying articles, especially for conveying sweets to be covered with a chocolate mass, are used in combination with a treating apparatus, especially a coating apparatus, in which the surfaces of the articles are covered with a chocolate mass, a different mass containing cacao butter or a similar fat containing mass. The articles may especially be bars. The essential element of the conveying apparatus is a grid belt. It is important that the grid belt includes a surface having openings on which the articles are supported to be conveyed through the treating apparatus. The openings of the grid belt allow for the chocolate mass and other coating masses to penetrate through the grid belt in a downward direction following gravity, to be collected and to be pumped through the circuit, again. Such conveying apparatuses including a grid belt are used in different treating apparatuses for articles. For example, they are used in the food processing industry to transport cookies and the like. In this case, the grid belt including openings allows for a different medium than chocolate mass, for example warm air, to penetrate through the grid belt and to flow about the surfaces of the cookies.
A coating apparatus for coating articles with a chocolate mass is known from German patent No. 38 39 440 C1. The coating apparatus includes a conveying apparatus including a grid belt. The endless grid belt is guided about a drive shaft and about one or more deflecting axes. The drive shaft includes gear wheels. The gear wheels with their teeth engage the grid belt to move the grid belt in the conveying direction.
Grid belts made of a web of steel are commonly known in the art. The web of steel includes a majority of bars substantially extending in a transverse direction with respect to the conveying direction of the grid belt Each single bar has a plurality of Z-shaped angled deformations. Usually, wire having a circular cross section is used for the web of steel and for the bars, respectively. Such a bar includes and forms, respectively, a majority of straight bar portions extending in a direction transverse with respect to the conveying direction. Additionally, there are U-shaped meshes with their slightly transverse oriented legs extending approximately in the conveying direction. The single adjacent bars are interconnected such that the endless grid belt is formed. Usually, it is sufficient to provide one drive shaft. The drive shaft is used in combination with a plurality of deflecting axes. The deflecting axes may include deflecting wheels. A motor is fixedly connected to the drive shaft. There may be a transmission. The gear wheels are arranged on the drive shaft such that they exclusively engage the straight bar portions of the web of bars to transmit torque necessary for the movement of the grid belt in the conveying direction. The legs of the meshes extend at a certain distance latterly from the gear wheels. The gear wheels usually engage the pulling bar portions of the grid belt. The lifetime of such a grid belt made of a web of steel is limited. The grid belt and the single bars of the web of bars, respectively, are subjected to bending forces during operation of the conveying apparatus. Due to forces being transmitted in the lateral periphery of the gear wheels, the bars are subjected to changing bending forces. The bars are bent at the same location again and again. Accordingly, there is the danger of fatigue fractures and repeated stress failures of the grid belt. Such fractures of the grid belt require a stop of the production until the grid belt has been removed and a new grid belt has been assembled, or until the broken grid belt has been fixed. Losses due to necessary stops of the production may be substantial.
Gear wheels having a deep continuous centered channel to prevent the danger of impurities accumulating in the deepenings between teeth in the center of the teeth are also known in the art. The gear wheels are designed to be smaller than the width of the straight bar portions of the web of steel such that the legs of the meshes extending in the conveying direction are located at a distance with respect to the faces of the gear wheels. The channel does not reduce the danger of fatigue fractures.